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Abstract:

The present invention relates to an apparatus for performing heat
treatment of a bodily cavity in a mammal. The apparatus comprises a
catheter intended for insertion into said bodily cavity, an inflatable
balloon surrounding a distal end of said catheter in a liquid tight
manner which balloon is adapted in use of said apparatus to be inflated
and dilated in said bodily cavity, control means operatively connected to
said balloon by at least one oscillation lumen and being provided with an
oscillation assembly adapted to drive a heat transmitting fluid within
said apparatus, and heating means adapted to heat said heat transmitting
fluid. Said control means are adapted to control pressure and
temperature of said heat transmitting fluid. The heating means have a
heat emitting portion and a heat receiving portion which is use of the
apparatus are positioned in thermal contact with each other, and which
are separable from each other.

Claims:

1. Apparatus for performing heat treatment of a bodily cavity in a
mammal, comprising a catheter intended for insertion into said bodily
cavity, an inflatable balloon surrounding a distal end of said catheter
in a liquid tight manner which balloon is adapted in use of said
apparatus to be inflated and dilated in said bodily cavity, control means
operatively connected to said balloon by at least one oscillation lumen
and being provided with an oscillation assembly adapted to drive a heat
transmitting fluid within said apparatus, and heating means adapted to
heat said heat transmitting fluid, said control means being adapted to
control pressure and temperature of said heat transmitting fluid, wherein
said heating means have a heat emitting portion and a heat receiving
portion which in use of the apparatus are positioned in thermal contact
with each other, and which are separable from each other.

2. Apparatus according to claim 1, wherein said apparatus is separable
into a reusable unit and a disposable unit, said disposable unit being
adapted to be sterile.

3. Apparatus according to claim 2, wherein said heat emitting portion is
positioned in said reusable unit and said heat receiving portion is
positioned in said disposable unit.

4. Apparatus according to claim 1, wherein said oscillation assembly
comprises a fluid compartment in fluid connection with said oscillation
lumen, a wall of said fluid compartment at least partly forming said heat
receiving portion.

5. Apparatus according to claim 4, wherein said fluid compartment is
connected to a proximal part of the oscillation lumen via a fluid inlet
opening and is connected to a distal part of the oscillation lumen via a
fluid outlet opening.

6. Apparatus according to claim 5, wherein said fluid compartment has an
at least partly conical shape, comprising a wider bottom portion and a
narrower top portion as seen in a vertical direction.

7. Apparatus according to claim 6, wherein said fluid inlet opening is
located near the bottom portion of the fluid compartment.

8. Apparatus according to claim 6, wherein at least a part of said bottom
portion of the fluid compartment at least partly forms said heat
receiving portion.

9. Apparatus according to claim 1, wherein said heating means are heated
by any of the methods chosen from the group of electric resistance
heating, induction heating, microwave energy heating, and semi-conductive
ceramic elements.

10. Apparatus according to claim 1, wherein said heat emitting portion is
a tempered surface and is in use of the apparatus positioned in
mechanical contact with the heat receiving portion.

Description:

FIELD OF THE INVENTION

[0001] The present invention relates to an apparatus for performing heat
treatment of a bodily cavity in a mammal. The apparatus comprises a
catheter intended for insertion into said bodily cavity, an inflatable
balloon surrounding a distal end of said catheter in a liquid tight
manner which balloon is adapted in use of said apparatus to be inflated
and dilated in said bodily cavity, control means operatively connected to
said balloon by at least one oscillation lumen and being provided with an
oscillation assembly adapted to drive a heat transmitting fluid within
said apparatus, and heating means adapted to heat said heat transmitting
fluid, said control means being adapted to control pressure and
temperature of said heat transmitting fluid.

TECHNICAL BACKGROUND

[0002] Heavy menstrual bleeding (menorrhagia) is a very common problem for
women, often occurring when a woman reaches the mid-thirties or early
forties. Menorrhagia has been treated by hysterectomy which is a surgical
method to remove the uterus. It is major surgery involving serious risks
and high costs for medical care. A new simpler method was developed at
the last decade of the 20th century using hot balloon dilation of the
uterus cavity causing necrosis and ablation of the inner lining of the
endometrium ending the bleeding.

[0003] The method is simple and fast and do not require a highly skilled
surgeon. Today is therefore hot balloon dilation used in an increasing
number of treatments and several 100.000 procedures annually performed in
the western world.

[0004] Hot balloon dilation of uterus is performed by the use of a balloon
catheter attached to a control unit. A deflated balloon in the distal end
of the catheter is introduced through the cervix into the uterine cavity,
where it is inflated and pressurised by a hot liquid during several
minutes for destruction of the inner layer of the endometrium. The
control unit is providing energy for the heating and pressure. The
pressurised balloon reduces the cooling effect of the blood perfusion
improving the necrotising.

[0005] Hot balloon catheters for the treatment of menorrhagia are
described for example in U.S. Pat. No. 4,949,718 (Neuwirth et al), U.S.
Pat. RE 37,651 (Wallsten), WO96/26695 (Claren). In U.S. Pat. No.
4,949,718 (Neuwirth) is a heater in form of electric resistance elements
located in the middle of the balloon. The catheter, which is sterile, is
attached to the non-sterile control unit providing i.a. electric power
for the heater. The sterile catheter is generally disposed after use.

[0006] The RE 37,651 (Wallsten)-document contains an important feature in
form of a forced circulation through a heater in a balloon. The
circulation which considerably increases the heat transfer to the
endometrium gives a more even necrotisation and also shortening the
treatment time. The circulation is achieved by first means located in the
sterile catheter, which is attached to the non-disposable part in which
second mechanical means are located causing a back and forth movement of
the first means and consequently of the liquid in the catheter. Two
counter acting back valves in the balloon will transform the back and
forth movement to a violent circulation of the liquid through the heater
in the balloon. The non-disposable part also provides electric power for
the heater, which may be a PTC-element.

[0007] In WO96/26695 (Claren) is a balloon catheter used, which is
attached to a tank filled with liquid and to a system consisting of a
peristatic pump for the circulation of the liquid between the tank and
the balloon. This device has several disadvantages compared to the
Wallsten device earlier described. There is a long heating up time for
the large amount of liquid and a risk for contamination of the pump
system and the large amount of liquid in the tank as it is used several
times. Furthermore a burst balloon would cause large amounts of
pressurised very hot liquid to flow out from the uterus causing damages
on the patient.

[0008] The Wallsten device has been improved during the years and is
marketed under the name of Cavaterm plus®. The improved device is
described in the patent EP 1 139 944 B1 (Wallsten et al), even if the
claims are directed towards means to adapt the balloon length to
different cavity sizes. Of particular interest are the FIGS. 4 and 5 with
the corresponding description, which are incorporated by reference. In
the shown embodiment is a heater and two counter acting valves
incorporated in the handle of the catheter.

[0009] There is still a need to further improve the devices using hot
balloon technology for treatment of i.a. menorrhagia by improving its
cost-efficiency and ensuring the safety for the patient. This is the
object of the present invention.

SUMMARY OF THE INVENTION

[0010] The object of the invention is achieved at least partly by an
apparatus for performing heat treatment of a bodily cavity in a mammal,
comprising a catheter intended for insertion into said bodily cavity, an
inflatable balloon surrounding a distal end of said catheter in a liquid
tight manner which balloon is adapted in use of said apparatus to be
inflated and dilated in said bodily cavity, control means operatively
connected to said balloon by at least one oscillation lumen and being
provided with an oscillation assembly adapted to drive a heat
transmitting fluid within said apparatus, and heating means adapted to
heat said heat transmitting fluid, said control means being adapted to
control pressure and temperature of said heat transmitting fluid, wherein
said heating means have a heat emitting portion and a heat receiving
portion which is use of the apparatus are positioned in thermal contact
with each other, and which are separable from each other.

[0011] By the division of the heating means into a heat emitting portion
and a heat receiving portion which are separable, two units may be
produced having each its own internal circuitry for heat and possibly
other supplies. By such a division of the apparatus the heat production
may be performed in one unit, which consequently contains the devices for
this production, and the produced heat may be transmitted to the other
unit. The unit receiving the produced heat may therefore be simplified in
design and shielded off from internal contact with the other unit. Hence,
the unit comprising the heat receiving portion may be liquid tightly
separated from the unit comprising the heat emitting portion and there is
no risk for contamination of the liquid by the contact with the unit
comprising the heat emitting portion. In the preferred embodiment of the
invention the unit comprising the heat emitting portion is the control
unit and the unit comprising the heat receiving portion is the catheter,
but the scope of the claims is by no means limited to this embodiment.
The unit comprising the heat receiving means, i.e. preferably the sterile
catheter, can be produced at low cost and therefore becomes better
adapted to be disposed after use if desired. Another advantage is that
the amount of liquid circulating enclosed in the apparatus becomes small,
which reduces serious burns if the balloon should burst. The heating up
time will hence also be short and it has been tested that although the
positioning of the heat emitting portion may be at a distance from the
inflatable balloon the heat loss in the oscillation lumen is in principle
negligible. Yet another advantage is that the unit comprising the heat
receiving portion is not by itself connected to any power unit and
therefore the patient is at no risk of being subjected to electric shock.

[0012] According to an aspect of the invention the apparatus is separable
into a reusable unit and a disposable unit, said disposable unit being
adapted to be sterile.

[0013] According to an aspect of the invention the heat emitting portion
is positioned in said reusable unit and said heat receiving portion is
positioned in said disposable unit. By the inventive apparatus it is
possible to divide the heating means into a low cost disposable part,
i.e. the heat receiving portion and preferably the catheter, and a high
yield reusable part, i.e. the heat emitting portion and preferably the
control unit. By locating the low cost means in the disposable catheter
and the technically much more elaborated and expensive means for the heat
production and heat emitting of the heating means in the reusable control
unit the apparatus will be improved in terms of environmental
friendliness and production costs.

[0014] According to an aspect of the invention the oscillation assembly
comprises a fluid compartment in fluid connection with said oscillation
lumen, a wall of said fluid compartment at least partly forming said heat
receiving portion. This way a simply yet efficient structure is achieved.

[0015] According to an aspect of the invention the fluid compartment is
connected to a proximal part of the oscillation lumen via a fluid inlet
opening and is connected to a distal part of the oscillation lumen via a
fluid outlet opening.

[0016] According to an aspect of the invention the fluid compartment has
an at least partly conical shape, comprising a wider bottom portion and a
narrower top portion as seen in a vertical direction. This way any air
enclosed in the liquid and/or the compartment will ascend to the top
portion where it collects and may be removed if required.

[0017] According to an aspect of the invention the fluid inlet opening is
located near the bottom portion of the fluid compartment. When the liquid
enters the compartment it hence enters close to the heat receiving
portion and is thus immediately exposed to the heat.

[0018] According to an aspect of the invention at least a part of said
bottom portion of the fluid compartment at least partly forms said heat
receiving portion.

[0019] According to an aspect of the invention the heating means are
heated by any of the methods chosen from the group of electric resistance
heating, induction heating, microwave energy heating, and semi-conductive
ceramic elements, such as PTC elements.

[0020] According to an aspect of the invention the heat emitting portion
is a tempered surface and is in use of the apparatus positioned in
mechanical contact with the heat receiving portion.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention is in the following described with the aid of
the accompanying drawings, which are merely included as non-limiting
representations of a preferred embodiment.

[0026] Throughout this application the words distal and proximal,
respectively, are intended to refer to a situation as seen in relation to
an operator or a user of the inventive apparatus.

[0027] Reference is made to FIG. 1 showing an apparatus for treatment of
menorrhagia by heat balloon ablation which is one form of heat treatment.
The apparatus comprises an ablation catheter 1 having a balloon catheter
3 with a balloon 8 and a conduit 4 containing a first lumen 4a and a
second lumen 4b, a connector 5 in the proximal end of the conduit 4 and a
control unit 2. The first lumen 4a is located within the second lumen 4b.
The control unit 2 is supplying electrical power and any other supplies
required to the apparatus in a known manner.

[0028] The first and second lumen 4a and 4b pass the connector 5 which is
partly inserted in the control unit 2 and provides connection between the
balloon catheter 3 and the control unit 2, and also via a conduit 6 from
a separate syringe 7, for filling and regulating the pressure of a liquid
within the apparatus. This liquid is one example of a heat transmitting
fluid as claimed in the claims. The inner second lumen 4b is adapted to
lead said liquid from the connector 5 to the balloon 8, and the outer
first lumen 4b leads the liquid back from the balloon 8 towards the
connector 5. Arrows indicating this are shown in FIG. 3.

[0029] The control unit 2 comprises an oscillation assembly for creating a
back-and-forth movement of a membrane in the connector 5, which in use
induces circulation of the liquid from the membrane through a compartment
9 in the connector 5 and through the first lumen 4a. The liquid then
passes through a second tube 32 in the balloon catheter 3 to the balloon
8, when the liquid returns through a first tube 31 connected to the
second lumen 4b in and further back to the compartment 9 in the connector
5.

[0030] During use, the lumens 4a and 4b, the corresponding tubes 31 and 32
in the catheter 3, the balloon 8 and the compartment 9 in the connector 5
create a liquid tight circuit circulating the sterile liquid. A heater 29
in the control unit 2 provides heat at a controlled temperature to the
liquid when circulating in the compartment 9.

[0031] The apparatus is divided into a reusable part which is intended for
multi-use, and a disposable part. The reusable part comprises the control
unit 2 and the disposable part comprises the ablation catheter 1, the
connector 5 and the conduits 4 and 6. The disposable part is in the
preferred embodiment intended to be sterile and used only once. The
disposable part establishes a well defined and from the surrounding
delimited internal system for supplies to the balloon 8 for the treatment
of the patient. The disposable part meets the reusable part via the
connector 5 which on its surface has contact portions suitable for
yielding heat energy from the reusable part to the liquid contained in
the disposable part. The claimed heat receiving portion is located on the
connector's 5 surface, and the claimed heat emitting portion, i.e. the
heater 29, is located within the pocket in the control unit 2 which is
adapted to receive the connector 5. When the connector 5 is positioned
within the pocket of the control unit 2 the heat receiving portion is
located adjacent the heat emitting portion. The connector 5 is insertable
into the control unit 2 and again removable therefrom.

[0032] FIG. 2a shows in more detail the connector 5 with the conduit 6 for
the inflation of the liquid from the syringe 7. A membrane 10 (positioned
in the same plane as the figure and actuated by the control unit 2 in a
known manner) induces circulation via a lumen 11 which is connected to
the compartment 9. The compartment 9, which has a small volume, has one
outlet 12 with a ball valve 13, and one inlet 14 with a ball valve 15.
The outlet 12 is connected to the first lumen 4a and the inlet is
connected to the second lumen 4b. The ball valves 13 and 15 are
counteracting and in use transfer alternating back-and-forth pulsation of
the liquid created of the membrane 10 to a stream of a liquid through the
lumen 4a and further through the lumen 4b in the conduit 4 as earlier
described. This is one embodiment of an oscillation assembly according to
the claims. The arrows in the figure indicate a positive stroke with the
ball valve 13 opened and the ball valve 15 closed. The figure also shows
a membrane 16 (positioned in the same plane as the figure) for connection
to a pressure sensor in the control unit 2 for indicating the pressure in
the balloon 8. The membrane 16 is connected to a safety valve 17 with an
exit 18. A valve for evacuation of air is depicted 19 and is positioned
vertically above the compartment 9. The performance of the inventive
apparatus is negatively affected if air is entering the system and it is
therefore desired to be able to evacuate any air contained in the liquid.
The bottom of the compartment 9 is heated from a heater located in the
control unit 2 (shown in FIG. 2b).

[0033] It is contemplated that the oscillation assembly and the conduit 4
may be designed to induce a pulsation to the liquid rather than a
circulation. In such a case there is no need for a first and a second
lumen within the conduit 4, but one single lumen for driving the liquid
back-and-forth. Likewise, then one single tube is needed to connect the
lumen to the balloon 8.

[0034]FIG. 2b shows a cross-sectional view A-A from FIG. 2a of the
connector 5. The compartment 9 has a circular and flat bottom portion 25
and an at least partially cone-shaped top portion and a lid 26 as seen in
the vertical direction, creating a fluid tight space for containing fluid
from which space the fluid exits to the lumen 4a during circulation. The
bottom 25 is wider than the top. The bottom 25 of the fluid compartment 9
is heated by a heater depicted 29 (dashed line) inducing heat provided in
the control unit 2. The heater 29 is a preferred embodiment of a heat
emitting portion according to the claims, and said bottom 25 is a heat
receiving portion correspondingly. A cut through the lumen 4a is depicted
27 and 28 depicts the membrane for back-and-forth movements. Preferably
the part of the connector 5 containing the fluid compartment 9 is made at
least partially of transparent material in order to allow visual control
of the fluid flow during operation of the apparatus. It is hence possible
to witness whether there is any air within the system. Air will be seen
as a bubble at the vertical top of the compartment 9. The inlet 14 to the
compartment 9 is located near the bottom 25 in order to maximise the
heat transfer to the liquid. The compartment 9 may be designed
differently, i.a. the compartment 9 may have a square bottom and a
uniform height extension or a rounded design.

[0035] The incorporation of the heater 29 in the control unit 2, the
heater 29 being in thermal contact with, but mechanically and
electrically separated from the fluid compartment 9 in the connector 5,
has many advantages which will be explained below. One out of several
benefits of this embodiment in comparison with the devices such as in EP
1 139 944 B1 (Wallsten et al) earlier referred to is that the design of
the balloon catheter can be considerably simplified in the absence of a
heating system within it, and thus can be better adapted for mass
production at much lower cost. This is also important from an
environmental point of view if the sterile catheter is to be disposed
after use. Furthermore, there is no way to contaminate the sterile liquid
by the control unit 2. Also, the heater 29 in the non-disposable control
unit 2 may be produced with improved quality and more efficient
technology may be chosen since it is used again and again.

[0036] It should be understood that the wording "thermal contact" is
intended to incorporate any manner of transmitting heat from the heat
emitting portion in the control unit 2 to the heat receiving portion in
the connector 5. Such manners may i.a. be electrical resistance heating,
induction heating or microwave energy heating, but any manner that is
found cost efficient and manageable in terms of size may be utilised.

[0037]FIG. 3 illustrates the simplified balloon catheter 3 partly in
cross-section. The balloon catheter 3 comprises an elongate tubular body.
In the proximal part is an insulated handle 30 provided for the operator
of the ablation apparatus 1.

[0038] The two concentric tubes 31 and 32 in the centre of the catheter
are in the proximal part 33 of the catheter attached to the conduit 4,
thereby creating a continuation of the lumens 4a and 4b. At the distal
end of the tube 32, which is longer than tube 31, is the inflation
balloon 8 fixed. The collar of the balloon 34 is fluid tightly fixed to
the distal part of the tube 31. In the distal part of the inner tube 32
are holes 35 provided creating inlets. Outlets 36 from the inner of the
balloon are provided in the space between the concentric tubes 31 and 32.
In use will the pressurised hot liquid circulate from the heating
compartment 9 through lumen 4a in the conduit 4 and the tube 32, through
the inlets 35, further through the balloon and the outlet 36 and back to
the heating compartment. The heater 28 in the regulation unit has means
for measuring and regulating the temperature of the fluid to a desired
level which preferably is about 80-95° C. if a water-based liquid
is used.

[0039] The embodiments of the invention that have been described above all
have heating means positioned in the connector 5 and the control unit 2.
However, the heating means may within of the scope of the claims be
provided outside the control unit 2. Noteworthy however is that the two
portions should be separable in order to achieve the effect
simplification of the one unit and maintaining the major heat production
parts in the other.